This invention relates to the art of film wrapping apparatus for use in wrapping objects with thermoplastic film, such as polyvinyl chloride wrapping film, and more particularly to improvements directed to dispensing film from a film roll.
It is known in the art to provide film wrapping apparatus which includes a support structure having an upper work surface at which items are to be wrapped in film with the film then being sealed and severed to complete a film enclosure around the item. An example of such a wrapping machine is provided by the Clamco Corporation and known as the Model 6500 machine. This is an automatic machine that employs a conveyor that receives items to be wrapped in film and a film wrapping device that encloses each item with film which is then severed and sealed about the item. The film is supplied to the wrapping apparatus from a film roll that is supported by a pair of cradle rollers located above the work surface. The film is pulled from the roll as it rotates about its axis of rotation. The film is pulled by means of a pair of pinch rollers of which one is driven by a motor with the film being guided past rollers in a downward direction to the work surface where the film is wrapped about an article.
One problem presented is the difficulty for an operator to position a roll of film, which may weigh on the order of 90 pounds, onto the cradle rollers located above the working surface and then thread the leading edge of the film through the pinch rollers and other guide rollers, all located above the work surface. It would be more desirable if the roll of film could be supported by cradle rollers located underneath the work surface and carried by a slidable drawer so that the drawer could be pulled out from the support structure of the film wrapping apparatus permitting the operator to load the film roll on the cradle rollers and then push the drawer back into its retracted position. It would be further desirable to provide some means for gripping the leading edge of the film so that as the film is pulled from the roll it is brought upward from a position below the working surface to a position essentially at or above the working surface. This would permit the operator to easily complete the threading of the film prior to commencing operation of the film wrapping apparatus.
There are examples in the prior art of film wrapping apparatus wherein a roll of film is mounted below the work surface at which the film wrapping takes place. Such examples include the machines disclosed in the U.S. Pat. Nos. to I. Feldman 3,800,499, D. B. Yeager 4,649,693, D. J. Rosenthal 3,595,456 and R. J. Skalsky et al. 4,936,079.
While each of these patents discloses a machine having cradle rollers or the like located below the work surface for supporting a roll of film, none of the patents teach the additional features of mounting the cradle rollers on a drawer which may be pulled out from the machine to enable an operator to load a roll of film on cradle rollers together with some means for gripping the leading edge of the film for withdrawing film from the roll, as the drawer is being closed, and then presenting the leading edge of the film to a position proximate the work surface to assist an operator in completing the threading of the film wrapping machine.